Contaminants-in-Fuel Diagnosis

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5095185 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions Circuit/System Description For an overview of the component/system, refer to: Fuel System Description The diagnostic tests for the following conditions of the fluid: Diesel Fuel Debris / Dirt Diesel Exhaust Fluid (DEF) Foreign objects Fungi / Microorganisms Gasoline Rust Water The conditions listed below can be caused by the following contaminates in the system: Diesel Exhaust Fluid (DEF) / Gasoline / Water Engine cranks but does not run Hesitation Misfire Stalling Reference Information Special Tools The options listed below are both acceptable for testing: Litmus Paper — 0 to 14 pH Litmus paper-based product that tests for diesel exhaust fluid (DEF) in fuel — Commercially Available Circuit/System Verification

1. Verify with the customer the following did not exist: Incorrect fluid was installed @ Fuel Tank — For example: Diesel Exhaust Fluid (DEF) or Gasoline ⇒ If a condition exists Refer to: Fuel System Cleaning ⇓ If no condition exists
2. Ignition/Vehicle » Off
3. Using an approved clear container, drain 150 mL (5.07 US fl oz) of fluid from the component: Fuel Filter Drain Plug » Refer to: Water-in-Fuel Draining
4. Place the container on a level surface for 1 min.

Note

Diesel exhaust fluid (DEF) or water will be clear in color and sink below the diesel fuel at the bottom of container. If the fuel system is contaminated with water, inspect the fuel system components for rust or deterioration.

5. Verify the condition does not exist: Diesel Exhaust Fluid (DEF) or Water @ Bottom of container ⇒ If a condition exists

Note

Make sure the litmus paper is at the bottom of the container to ensure the correct test results 5.1. Install » Litmus Paper @ Bottom of container — For 10 to 15 s 5.2. Remove » Litmus Paper

Note

DO NOT allow the litmus paper to dry as it will lose its pigmentation and will no longer be able to detect the presence of diesel exhaust fluid (DEF). 5.3. Compare the color of the litmus paper to the supplied color scale. Within 1 min Verify the pH level is less than 10 pH ⇒ If the level is 10 pH or greater » Refer to: Fuel System Cleaning ⇓ If the level is less than 10 pH 5.4. Refer to: Fuel System Cleaning & Water-in-Fuel Draining ⇓ If no condition exists

6. Verify the condition does not exist: Fuel — Cloudy / Dirty / Foreign objects / Rust ⇒ If a condition exists Refer to: Fuel System Cleaning ⇓ If no condition exists
7. Remove the component: Fuel Filter
8. Verify a condition does not exist with the component: Fuel Filter & Fuel/Water Separator Reservoir — Debris / Dirt / Fungi / Microorganisms / Rust / Water ⇒ If a condition exists Refer to: Fuel System Cleaning ⇓ If no condition exists
9. Perform the following procedure/test: Fuel Specific Gravity Testing Verify the procedure/test passes. ⇒ If the procedure/test does not pass Repair as necessary ⇓ If the procedure/test passes
10. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification